Caliper clearance
 

Looking into getting a set of snow wheels/tires. I'm considering Mandrus wheels and going down from the 19' OEM I have on, to an 18 inch wheel, then with non-run flats. I think that'll make things super cush. Since the E450 wagon comes with 18 inch wheels for 2019 too I was hoping it'll be an easy fit. But looking at the inside diameter (the measurement important for caliper clearance,sometimes called "x-factor"), is only 16-5 inches or so. The outside diameter is actually 20 by my tape measure, but it's clearly considered a 19inch rim/tire. MOst of the wheel/ tire sites don't list x-factor at all. Even the nice wheel-size.com calculator site doesn't mention inner diameter much.

Anyway, at the top and bottom of my caliper the clearance is only a finger thickness with the 19's. I understand wheel makers will changes the lip and rim thickness with different overall sizes. But I'm not looking to get stuck with a wheelset I can't use. But also would like to go down to 18's rather than just accept their "guaranteed" 19" recommendation. The stock 19" 10 spokes do seem to have a thick lip, so I'd hope 18s work fine.

Are there wheel standards that say x-size wheel will have z size inner diameter?

CarID has a "guaranteed fitment" but only on the 19' ones. Almost every wheel/ tire site doesn't have an up to date vehicle selector (including MB own tire package site for that matter.)

Any thoughts? Thx.

I can't help you, but if you do a search around here, you'll find loads of threads on this very subject. Hopefully, someone who bought winter tires for their car will chime in.

You could start with this: https://mbworld.org/forums/search.php?searchid=23356122

I had done the search, hence the new thread. There's some great Official Wheel threads for older models, but doesn't look like we're quite there yet on the s213. Nothing that quite addresses my questions. Loads of wheel posts, but much less specific.

I'll have to give the wheel mfr a call. And post results once I'm all set up.

Check the Tire Rack (winter tire/wheel package section). There are a number of choices in 18" including by Rial (one of Mb's OEM wheels suppliers), I.E. Rial M10 (looks OEM, uses OEM bolts) in several colors. Incredibly priced too.

I am running 18 inch aftermarket wheels on my '17 E400 wagon . I previously had these wheels on my '12 e63 wagon. Clearance was tight on the E63 but lots of room on the E400. You will like the slightly cushier ride.

I'm a big Tire Rack fan. I've bought a couple sets of wheel packages and am always thrilled with the price and speed of delivery.

Their aftermarkets are sized with huge bores usually, then they use the hubcentric rings to fit them to various OEM size hubs. While one can run hubcentric rings, I've fussed with those too many times- whether premium/ plastic, OCD lugbolt tightening and grease to get them as perfect as possible- but nothing works as well as proper bore size and no rings. Its at the higher speeds you'll really notice it.

[Edit: the Rials do not need hub rings. Yes! & Thanks!]

I can of course just go to the dealer and get MB setups. But that's more expensive, lower quality, heavier wheels and a limited set of package sizes they consider "official"- the dealer is getting back to me on whether they can do 18" on my E450. I wondered if there were any changes at all to the E450 brakes, vs 18" E400 4matic sedan (more typically listed on the tire/wheel sites). Or even if any of the packages I ordered alter the brake size- doubtful I'd assume, but I need to verify. Otherwise I can't really extrapolate from other posts' experience.

I should be able to get my question answered from the wheel mfr and just measuring myself. I just wondered if there were any standards for overall wheel size diameter also telling us something specific about the inner diameter for brake clearance. The wheel size calculator websites don't mention it really, within all their other measurements. Unless, I'm missing something obvious. (very possible with me.)

My E450 calipers don't have much clearance at each end of the caliper with the 19' MB 10 spokes it came with . Plenty of room around the rest of the wheel. But I'm afraid they might not have 1/2 inch to give on each side if I went down from 19 to 18 for my winters. There is just enough room for my index finger thickness, which touches both caliper and wheel. (most threads discuss going up in size.) Now, the OEM wheel does seem to have a nice thick flange lip to it's drop center. But the sites/ don't make it easy to know that clearly without measuring it it seems. Probably, but I can't return mounted tires and wheels, so need to be 100%. I was wondering if there was some industry standard I was unaware of. Like "A 19" wheel always means at least x for the inside diameter (caliper clearance) and "An 18" wheel always means x for it's inside clearance.

Seems like a fundamental thing sites would list. At least the actual mfr themselves. But no dice.

Thanks- do you know your wheel model name? I'm hoping for even cushier!

I should have investigated further! Those Rial's do indeed NOT need hubcentric rings. Should be a home run price wise! I'll let people see the final result.

Thanks 3MB’s. Jumped on the Rials. A basic set of winters for cheap that fit well, OEM hub bore. MB caps. It’s indeed clear they make Mb stuff. The hub covers are identical plastic other than logo. Caliper clearance is quite tight, but should clear pea size gravel and salt should it get in.

The ride on these x-ice is wonderful. 1 inch smaller wheels plus non-run flat! I don’t understand how some people claim to not notice the difference.

Very happy. Looking forward to needing some summer tires soon enough.

Photos